In 2014, more than 11 million people abused and more than 2 million people sought treatment for opioid use disorder (OUD). Maintenance on an opioid agonist like methadone is a common form of treatment for OUD and more than 113,000 individuals in the US initiate opioid maintenance treatment (OMT) annually. Up to 62% of patients who are maintained on methadone for OUD report continued and persistent chronic pain that is associated with poor OMT treatment outcomes. There are no empirically-supported methods for treating pain in OMT patients and a study we conducted observed that only 29.3% of these patients receive pain treatment. Methadone that is dispensed for pain to the general population is administered twice or thrice daily, however methadone that is dispensed for OUD is administered as a single bolus dose, and it is neither practical nor even feasible for methadone clinics to allow patients who experience chronic pain to attend the clinic for more frequent dosing. Existing methods to manage take-home dosing of methadone in OUD patients are not adequate to manage the split-dosing procedure that would be necessary to empirically evaluate whether changing the schedule of methadone dosing will effectively manage concurrent pain and OUD. This R34 project-planning grant proposes a rigorous within-subject study with a choice procedure to evaluate whether a commercially available electronic pillbox will effectively and securely allow us to split a patient?s prescribed methadone dose into smaller ( dose) units that can be consumed as take-home doses (versus the single daily dose currently prescribed) in support of an R01 study. This R34 will enroll 54 patients (n=27 men, n=27 women) into a 12-week evaluation. Participants will complete treatment-as-usual (TAU) and electronic pillbox phases. Each phase will be 4 weeks in duration, the order of phases will be randomized, and all participants will undergo both phases. Participants will then complete a final 4-week choice phase wherein they will choose whether to continue with the TAU or electronic pillbox condition. Primary outcomes will be measures of patient and staff feasibility, acceptance, and satisfaction with the approach, as well as changes in concurrent use of illicit drugs and opioid withdrawal symptoms as a function of changing to twice-daily dosing. Secondary outcomes will be preliminary data in changes in pain severity following the transition to twice-daily dosing. All results will be analyzed for the entire sample and as a function of participant sex and race. We expect both staff and patients will find the pillbox feasible, acceptable, and satisfactory, that it will not lead to an increase in drug relapse or opioid withdrawal symptoms, and that patients will experience less severe pain relative to baseline conditions. The next step will be to empirically examine whether splitting the routinely prescribed methadone dose from once to several times daily reduces pain among methadone-maintained patients using a randomized, double-blind, placebo-controlled trial. Together, these two studies (R34 + subsequent R01) are poised to collect the feasibility and efficacy data that will be necessary for OMT clinics to adopt this treatment.